The present invention relates generally to sampling devices, and more particularly, to sampling devices that are constructed, arranged, and made with such materials that the devices may economically be thrown away after a single use, or after only a few uses. The products to be sampled are liquids in containers, including liquids that may have one or more layers of sludge or sediment at the bottom of the liquid.
In recent years, there has been growing concern from the standpoint of environmental protection with disposition of industrial waste materials, especially chemical waste. Whether motivated by a desire to avoid adverse affects to the environment, or simply to comply with the numerous laws and regulations affecting waste disposal, chemical users of every description have become increasingly aware of the prohibitions against indiscriminate disposition of waste materials, particularly those containing any reactive chemicals, any solvents, non-biodegradable oils and the like. Various hazards are associated with many waste chemicals, including many chemicals previously thought to be relatively benign from a health or ecology standpoint.
As the ability of chemical manufacturers to modify simple oils, solvents and other reagents to assist them dispersing other liquids and solids within them has increased, whereby a great variety of materials, particularly liquids and finely subdivided solids are emulsified, coupled or rendered soluble within a solvent or external phase carrier, the potential for transporting diluted materials to unattended or uncontrolled disposal sites has increased greatly. Consequently, in many modern industrial processes, waste materials are generated which are toxic, dangerous or undesirable simply because they have small quantities of toxic materials disposed within what might otherwise be an innocuous material. Many materials, while not toxic at a particular time, may be converted into toxic wastes or may be leached out of inert or benign carriers. Of course, some solvents and other chemicals create waste disposal problems per se.
However, as concern with disposal has grown, an industry has emerged which is devoted to safe disposition of chemical wastes of various kinds. The basic premise for safe disposition of dangerous or questionable chemicals is that, once the product to be disposed of is identified, the nature of the risk it holds out can be assessed and proper steps may be taken to dispose of the chemical. From a theoretical standpoint, this approach is sound and serves as a basis for most, if not all, commercial chemical waste and disposal operations. However, practical problems of achieving chemical waste disposal remain substantial, and remain in need of continually improved approached to make headway in safe disposal practices. Many of these problems are then able to be overcome, when the nature of the product to be disposed of is fully understood.
Through ignorance or mistake, if the presence of a harmful material is unknown or is overlooked, the potential for an improper disposition method, and hence downstream environmental damage is greatly magnified. In other words, the more likely it is that the waste disposer is unaware of the nature of the material to be disposed of, the more likely it is that a proper disposition will not result.
As a consequence of the foregoing situation, there have been on-going requirements for waste disposers and/or recyclers to analyze waste stream materials to ensure that such materials are in fact as they are represented to be by the generators thereof. If materials inbound to a licensed disposer are of an unknown character, they will require detailed analysis. Consequently, although there has been a great increase in the technical ability of waste disposers and recyclers to analyze incoming materials, particularly liquids, sampling procedures for the incoming materials can themselves be the subject of mistakes and errors, as well as a source of unduly high cost. By way of example, with incoming waste being readily able to be analyzed on the basis of parts per million, and in many cases, industrial instrumentation being capable of identifying contaminants present in only parts per billion quantities, it is essential that the sampling process itself not only be done economically and reliably, but that it does not become a source of error in and of itself.
Thus, in the case of a drum of inbound liquid waste, for example, it is necessary for analysis that a representative sample of the material be taken. This implies that, particularly if there are materials of various densities present within a single container, that a sample be taken which accurately represents the entire material, i.e., that the sample contains elements from top to bottom of the container. In other words, the sample taken should replicate as closely as possible the exact make-up of the material being sampled.
If a sampling device is used repeatedly, it is necessary then either to clean the device after each use to avoid contamination by way of "carry over" or cross-contamination. Often, the cleaning process involved the use of solvents, aqueous emulsifiers or the like and this can lead to a false reading in one or more successive sampling operations. Therefore, it would be desirable to have a sampling device which would be manufactured economically enough to be thrown away after one use, or which could at least be made of relatively inert materials and capable of reliable cleaning without compromising performance.
It would also be desirable to have a sampling device, which although made from a low cost material, would still be highly reliable and potentially accurate in use.
In addition to having the foregoing characteristics, a sampling device should be one which is fool-proof in use and which permits accurate replication of the container contents during the sampling process. According to the present invention, this is achieved by providing a sampling device including a retention tube, a tube plug unit, and an operating rod and handle, with the tube being simple and economical and the plug and operating rod and handle being arranged to perform the multiple functions of sample gathering and retention in an extremely reliable manner at low cost.
In view of the failure of the prior art to provide a reliable, low cost sampling device, particularly for withdrawing liquid specimens from drums or other containers, it is an object of the present invention to provide an improved, low cost sampling device for liquids and the like received in shipping or storage containers and desired to be analyzed before shipment or treatment.
Another object of the invention is to provide a low cost sampling device which includes three extremely simple, low cost components including a retention tube, a multi-function plug unit and a multi-function operating rod and handle unit.
Still another object of the invention is to provide a sampling apparatus which may be made in a variety of sizes, particularly length, and thus be adapted to sample fluids within a variety of container sizes and styles by varying only the length of the tube and the rod and handle unit.
Yet another object of the invention is to provide an apparatus which may be inserted into the plug-receiving opening of a liquid containing drum or the like with the plug adjacent but spaced from the tube end, lowered to a desired depth while keeping the lower tube end open and then, by using a built-in gauging system comprising a novel arrangement of the rod and handle, capture a sample by moving the rod slightly to ensure that the tube is closed and the sample is trapped therein without disturbing the representative character of the sample.
A further object of the invention is to provide a sampling device wherein the plug unit includes a receiver for the lower end of the operating rod, a transverse plug head portion, a peripheral plug skirt with a tapered skirt seal, and wherein the plug head is supported by tapered ribs or the like serving as pilot surfaces for guiding the plug into the open end of the tube and closing off the lower tube end.
A still further object of the invention is to provide a multi-position engaging arrangement between the upper end of the operating rod and handle and the upper tube end, by providing a curl and transverse section of the rod end, with the transverse section being offset from the rod shank whereby the transverse portion may rest atop the tube end in one end position and whereby the tube end may engage a portion of the curl in another plug position.
Another object of the invention is to provide a sampling system wherein the retention tube is made simply from a length of polypropylene or other chemically inert plastic tubing and wherein the other components are also made at low cost.
A still further object of the invention is to provide an arrangement as described wherein a fine or vernier adjustment of the plug position relative to the rod may be achieved in a simple manner.
An additional object is to provide a sampling device which inherently reproduces a specimen which is representative of the liquid in which the tube is immersed, inasmuch as the tube is designed to extend from a position adjacent the top to a position in contract with or very near the bottom of the container.
A still further object of the invention is to provide a device wherein the portion of the plug may also be used to contact or sample sludge or other materials lying at the bottom of the drum or other container being sampled, or to exclude such materials from the sample-taking process.
The foregoing and other objects and advantages of the invention are achieved in practice by providing a sampling device including a hollow sample retention tube with open top and bottom ends, an operating rod and handle terminating at its upper end in a loop or curl and a transverse end portion for respective engagement with an edge of the upper tube and having attached at its lower end to a plug body having a head, a skirt, a peripheral seal for the skirt, and plural tapered support ribs extending from one part of the plug body to the radially outer portions of the plug head and serving as pilot surfaces for guiding the plug end into a desired position within the tube interior.
The manner in which the foregoing and other objects and advantages are achieved in practice will become more clearly apparent when reference is made to the following detailed description of the preferred embodiments of the inventions set forth by way of example and shown in the accompanying drawings wherein like reference numbers indicate corresponding parts throughout.